The computer world has a rich history of hackers who steered the progress of computer science and gave shape to computers, the internet, and networking as we see it today - in some cases single-handedly. While the term “Hacker” today carries a negative connotation of an ill-intentioned computer genius, that’s only a small portion of what the word really means. Yes, there are the Black Hat hackers behind internet mayhem, thievery, and chaos, but there are also White Hat hackers who use their computer savvy for good. There’s also a different kind of hacker entirely: the tinkerer. They all played parts, big and small, in creating the computer world as it exists today. We’ve put together a list of 10 great hackers who all played a part in this history.

Konrad Zuse

It all begins with Konrad Zuse, arguably the very first computer hacker. He may not have been a hacker in the modern sense of the word, but none of it would have been possible without him. You see, Zuse made the world’s very first fully programmable (Turing-complete as they say) computer, known as the Z3. It began, of course, as the Z1, and while it wasn’t built in a cave with a box of scraps, Zuse did build it himself in his parents’ apartment, completing it in 1938. Zuse eventually gained some backing by the German government, leading to the evolution from the Z1 to the Z3, which, complete in 1941, is considered the mother of modern computing.

John “Captain Crunch” Draper

John Draper was hacking computers long before computers were even common place. Draper’s hacking heyday was back in the early 1970’s, when the largest computer network to which the general public had any access was the telephone system. At the time, telephones were managed by an automated system using specific analogue frequencies which could be exploited to make free long distance or even international calls. It was called “Phreaking,” and one of the most well-known Phreaking tools was a toy whistle that came in a box of Cap’n Crunch cereal. With this whistle, Draper created another popular Phreaking tool known as the Blue Box, a device that could produce many other tones used by the phone companies.

Steve Wozniak

A contemporary to John Draper, Wozniak was no stranger to Phreaking. In fact, after Draper shared the details of his Blue Box design during a Homebrew Computer Club meeting, Wozniak built a version of his own. Steve Jobs saw the marketing potential in the device, and the two Steves began their first joint venture together. Wozniak’s hacking days weren’t all spent on projects of questionable legality, though. With the proceeds from their blue boxes as well as selling Wozniak’s cherished HP calculator and Jobs’ VW van, Wozniak created the Apple I. With the other Steve’s marketing prowess, their company became the industry leader it is today.

Robert Tappan Morris

As a graduate student at Cornell University, Robert Morris created his claim to fame: the computer worm. According to Morris, he created the worm as an attempt to gauge the size of the internet at the time. After its release on Nevember 2nd, 1988, the Morris Worm went on to infect approximately 6,000 systems (about 10 percent of the internet attached computers at the time). The worm was intended to be unobtrusive, but due to a flaw in its replication algorithm, it copied itself excessively, causing heaving system loads and ultimately leading back to Morris. In 1989, Morris became the first person indicted and later convicted under the Computer Fraud and Abuse Act of 1986.

Mark “Phiber Optik” Abene

Here’s a name you may not be familiar with: Mark Abene. He never hacked into the D.O.D. nor did he steal millions of dollars in some Swordfish-style bank heist. What he did do was piss off AT&T. As a member of the hacker group Masters of Destruction, Abene was often poking around on AT&T’s systems. When AT&T’s telephone system crashed, leaving 60,000 customers without phone service for over 9 hours, they quickly blamed Abene. The Secret Service paid him a rather aggressive visit, confiscating his equipment, and while AT&T eventually admitted that the crash was a mistake on its part, Abene was charged with computer tampering and computer trespassing in the first degree. Later, he would face more charges and ultimately serve a year in federal prison, making him the first hacker to do so.

Kevin “Dark Dante” Poulsen

Poulsen holds claim to one of the more amusing hacks of all time. A radio contest held by KIIS-FM promised a shiny new Porsche 944 S2 to the 102nd person to call into the station. Rather than try his luck among the multitude of Los Angeles listeners, Poulsen took over all of the telephone lines to the station to ensure he’d be the 102nd caller. He eventually had to disappear once he became a fugitive of the FBI. This landed him a spot on the popular TV show Unsolved Mysteries. The show’s hotlines crashed when the episode aired. Coincidence? In 1991, Poulsen was arrested and eventually pled guilty to various counts of computer fraud, money laundering, and obstruction of justice. Interestingly, since his incarceration, Poulsen made a complete 180, helping in cyber crime cases, and even capturing sexual predators on MySpace.

Kevin Mitnick

Kevin Mitnick is perhaps the most famous hacker in computer history, likely due to his being the first hacker to make the FBI’s Most Wanted list. As a master of social engineering, Mitnick didn’t just hack computers; he hacked the human mind. In 1979, at the age of 16, he hacked his way into his first computer system and copied proprietary software. He would often engage with admin personnel, such as in phone calls and e-mail messages, and trick them into giving up passwords and other security information. After a two and a half year pursuit, Mitnick was finally arrested and served five years in prison. He now runs his own computer security consultancy, Mitnick Security Consulting LLC.

Tsutomu Shimomura

Not all hackers fall under the Black-Hat umbrella. Tsutomu Shimomura is a White-Hat hacker credited with capturing Kevin Mitnick. In 1994, Mitnick stole some of Shimomura’s personal files and distributed them online. Motivated by revenge, Shimomura came up with a trace-dialing technique to back-hack his way in to locating Mitnick. With Shimomura’s information, the FBI was able to pinpoint and arrest Mitnick.

Richard Stallman

In his early years, Stallman was a graduate student and programmer at MIT’s Artificial Intelligence Labs where he would constantly engage with MIT’s rich hacking culture. As an advocate for just about everything Open Source, Stallman fought back when MIT installed a password system in its Computer Science department. He would decrypt users’ passwords (not an easy task given the processing power of the 1970’s) and send them a message with their password in plaintext, suggesting they leave the password blank in order to re-enable anonymous use. Going into the 1980’s, Stallman didn’t like the proprietary stance many manufacturers were taking on their software. This eventually led Stallman to create the GNU General Public License and GNU operating system, a completely free Unix-like OS that is completely Unix-compatible.

Linus Torvalds

Following Stallman’s lead, Linus Torvalds is another White-Hat hacker. His hacking days began with an old Commodore VIC-20 and eventually a Sinclair QL, both of which he modified considerably. On the QL in particular, he programmed his own Text Editor and even a Pac-Man clone he dubbed Cool Man. In 1991, he got an Intel 80386 powered PC and began creating Linux, first under its own limited license but eventually merged it into the GNU Project under the GNU GPL. Torvalds hadn’t originally intended on continued support for his Linux Kernel, but due to the nature of the Open Source project, it grew into one of the most hacker friendly (and secure) operating systems available.